Dual-QDs ratios fluorescent probe for sensitive and selective detection of silver ions contamination in real sample

Silver ions, as a commonly used industrial heavy metal, tends to deposit in the body and induce many diseases. In this work, modified CdTe QDs with green and red emission were synthesized to assemble dual-QDs, which could be efficient and selective utilized for Ag⁺ determination through the electron transfer progress between surface functional group of dual-QDs and Ag⁺, and the aggregation of Ag⁺ on the surface of dual-QDs. Under the appropriate pH value and volume ratio, the interaction between the surface functional groups of assembled dual-QDs reduce the affinity of Hg²⁺ in this system. The fluorescent signal of dual-QDs simultaneously attenuation or enhancement in the same proportion remove the interference of Cu²⁺ and other metal ions. Therefore, this method can selectively detect Ag⁺ without any masking agents. The linear region of detection was from 0 to 800 nmol/L (R² > 0.998), and low of detection (LOD) was 7.7 nmol/L, which could meet the corresponding standards of World Health Organization (WHO) and Environmental Protection Agency (EPA). This effective proposed dual-QDs ratios fluorescent probe has been applied to detect Ag⁺ in real environment water, tea and Citri Reticulatae Pericarpium (CRP) water.